Abdur-Rahmaan Janhangeer wrote: > saw this snippet on the internet : why assigning by index propagates it > all?
It doesn't. > >>>> a = [[1]] * 7 >>>> a > [[1], [1], [1], [1], [1], [1], [1]] > >>> a[0][0] = 2 >>>> a > [[2], [2], [2], [2], [2], [2], [2]] > > why not > > [[1], [2], [2], [2], [2], [2], [2]] As to why you'd expect that one I've no idea. > ? > > thank you ! a = [[1]] * 7 creates a list containing seven references to the same inner list [1]. With seven distinct lists you get the expected >>> a = [[1], [1], [1], [1], [1], [1], [1]] >>> a[0][0] = 2 >>> a [[2], [1], [1], [1], [1], [1], [1]] -- https://mail.python.org/mailman/listinfo/python-list
